While the TPM expects and returns the data in big-endian, the SAPI
implementation converts it to native-endianness. As stated in the
SAPI specification (section 3.2):
8. All SAPI data SHALL be in native-endian format. This means that
the SAPI implementation will do any endian conversion required for
both inputs and outputs.
So to use the exponent in a chunk we have to convert it to big-endian again.
Fixes: 7533cedb9a ("libtpmtss: Read RSA public key exponent instead of assuming its value")
Each private key object created to access a key residing in a TPM 2.0
creates a context structure used for communication with the TSS.
When multiple IKE SAs are established at the same time and using the
same private key, it is possible to make concurrent calls to the
TSS with the same context which results in multiple threads writing
to the same place in memory causing undefined behaviour.
Fix this by protecting calls to the TSS with a mutex unique for
each TPM 2.0 context object.
Up to now it was assumed that the RSA public key exponent is equal to 2^16+1.
Although this is probably true in most if not all cases, it is not correct
according to the TPM 2.0 specification.
This patch fixes that by reading the exponent from the structure returned
by TPM2_ReadPublic.
Closesstrongswan/strongswan#121.
Andreas Steffen